US Patent 7758407 Ventilation control based on occupancy

An arrangement for use in an occupancy-based ventilation system includes a plurality of CO2 sensors and a processing circuit. The plurality of CO2 sensors are disbursed throughout a plurality of spaces in a building. The processing circuit is operably coupled to receive information representative of CO2 measurements generated by the plurality of CO2 sensors. The processing circuit is operable to determine a value corresponding to occupancy, based on information from the CO2 sensors, and to control the flow of fresh supply air into the building ventilation system based on the determined value.